Hello.
I have got "almost ready" 2.6.30.10 linux kernel for Atmel's
AT91SAM9G20 CPU. The mainboard has one port connected directly to USB
device and the second port connected to TI's TUSB2046B USB hub.
The problem is:
CDC-ACM modem (Motorola G24) connected to 9g20 usb port directly works
fine but connected thru tusb2046b hub some data are lost (instead of AT
echo I sometimes get A or T only) and another time I got input/output
error. The test script uses chat, cycled: open ttyACM0 port, send AT and
wait for OK, close the port.
When I compiled the kernel with usb debug option I got (only during
communication thru the hub) at91_ohci cc 5 -> status -62 (ETIME) error.
Now I am going to use usbmon and I started to learn USB low level
protocol.
I also found the hub's errata
http://www.ti.com/lit/er/sllz051/sllz051.pdf and some codes:
http://www.clearchain.com/blog/posts/resetting-the-usb-bus-under-linux
http://marc.info/?l=linux-usb-users&m=116827193506484&w=2
However my modem is detected properly. Therefore usb port reset seems
another problem solution.
Can you give me any advice/clue/tip?
I don't want to update the kernel. According to my experience it does
not guarantee of stable system and generates a lot of work again.
I used:
- 2.6.30 vanilla linux kernel
- the patch from
http://maxim.org.za/AT91RM9200/2.6/2.6.30-at91.patch.gz
- the patch from
http://www.at91.com/linux4sam/bin/view/Linux4SAM/LinuxKernel,
2.6.30-at91-exp.4.patch
- (after problem detection, not helped) 2.6.30.10 patch
best regards
Janusz Uzycki
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